Were tiers working before lockdown?

Beware data that is released on the eve of a Commons vote on lockdown restrictions. That was the lesson of the graph presented by Sir Patrick Vallance at the Downing Street press briefing on 31 October, which included a scenario of 4,000 deaths a day by December unless drastic action was taken. The figure quickly fell apart when it was revealed that the data was several weeks out of date and the curve shown on the graph was already running well ahead of reality. What, then, to make of the React study published this morning, reported on the BBC news and elsewhere this morning, claiming that Covid cases have ‘fallen by about a third over lockdown’? Does the research show that cases fell because of lockdown?

This idea that cases fell as a result of lockdown suits the government’s narrative as it seeks Commons support for a new tier structure that is notably more severe than the system it replaces — both in terms of the rules applied to each tier and the extent of the areas put into the higher tiers.